[en] Plasticizer-free methyl methacrylate-decyl methacrylate (MMA-DMA) microspheres were prepared under mild, non-reactive conditions using a high-throughput particle generator. The particles were perfectly smooth and monodisperse, with a particle diameter of approximately 10.0 μm. In order to evaluate the suitability of the polymer as a matrix for bulk extraction processes, lipophilic sensing components were incorporated into the particles. Particles contained either a H⁺-selective chromoionophore (ETH 5294) only (type 1), or a K⁺-selective ionophore (BME-44), anionic sites (NaTFPB), and ETH 5294 (type 2). Type 1 particles responded according to an anion-proton coextraction mechanism and demonstrated Hofmeister selectivity by showing a preference for more lipophilic sample anions (ClO₄^->NO₃^->Cl^-). Particles of type 2 functioned by way of an ion-exchange equilibrium and demonstrated a functional response for K⁺, with a dynamic range from 10^-1-10^-4 M K⁺. These particles also exhibited selectivity comparable to that previously reported for analogous particles made from bis(2-ethylhexyl sebacate) (DOS)-plasticized poly(vinyl chloride) (PVC) and DMA-DOS. In addition, the behavior of both types1 and 2 particles was in agreement with analogous thin film optical sensors (optodes) prepared from MMA-DMA. With the advent of ionophore-based plasticizer-free microspheres a wide variety of ions may potentially be assessed using various popular bead-based sensing strategies, such as lab-on-a-chip technologies, bundled optical fiber arrays, and flow cytometry, without experiencing the deleterious effects resultant of plasticizer leaching

[en] At present, in many preclinical and clinical studies, the mechanism of action, combination therapy, therapeutic efficacy, and side effects of vascular endothelial growth factor (VEGF) inhibitors in combination with radiotherapy and immunotherapy are being explored. Some studies have reported improved tumor control after the addition of anti-VEGF intervention to radiotherapy. Nevertheless, how to administer these three modalities to achieve optimal response with minimal toxicity remains to be investigated. In this article, the mechanism and research progress on anti-VEGF therapy, radiotherapy and immunotherapy were reviewed. (authors)

[en] Highlights: • The adsorption sensitivity of SWCNTs doped with Ni atom toward SO_2 molecules was studied for the first time. • The adsorption capability of Ni-doped SWCNTs improved gradually with the increase of tube diameter in the small range. • Ni-doping decreased the primary symmetry of SWCNTs and the adsorption sensitivity was enhanced with the decrease of broken symmetry factor. • Ni-doped SWCNTs have much higher adsorption energy, larger net charge transfer values and shorter binding distances than pure SWCNTs because of chemisorption of the SO_2 molecule. - Abstract: The adsorption of SO_2 molecules on the surfaces of Ni-doped single-walled zigzag (n,0)CNTs (n = 4,5,6, Ni-SWCNTs) has been investigated using density functional theory. The adsorption energies and changes in geometric and electronic structures after the adsorption were analyzed to characterize the sensitivity of Ni-SWCNTs toward SO_2 molecules. Our calculated results showed that Ni-SWCNTs had much higher adsorption energy, larger net charge transfer values and shorter binding distances than pure SWCNTs owning to chemisorption of the SO_2 molecule. The obtained density of states and frontier orbitals demonstrated that the orbital hybridization was obvious between the SO_2 molecule and Ni-SWCNTs, while there was no evidence for hybridization between SO_2 molecule and pure SWCNTs because of weak physisorption according to the total electron density maps. After doping of Ni atom, the primary symmetry of SWCNTs decreased, which enhanced the chemical activity of SWCNTs toward SO_2 molecules consequently. Furthermore, the adsorption capability of Ni-SWCNTs was improved gradually with the increase of tube diameter in the small range. The above results have profound meaning for the design and fabrication of SO_2 sensing devices

[en] Properties of plasmon excitations in two-dimensional (2D) atomic cluster systems are theoretically studied within an extended Hubbard model. The collective oscillation equations of charge, plasmon eigen-equations and the energy-absorption spectrum formula are presented. The calculated results show that different symmetries of plasmons exist in the cluster systems, and the symmetry of charge distribution in the plasmon resonance originate from the intrinsic symmetry of the corresponding eigen-plasmon modes, but not from the symmetry of applied external fields; however, the plasmon excitation with a certain polarization direction should be excited by the field in this direction, the dipole mode of plasmons can be excited by both uniform and non-uniform fields, but multipole ones cannot be excited by an uniform field. In addition, we show that for a given electron density, plasmon spectra are red-shifted with increasing size of the systems.

[en] A novel three-dimensional (3D) hierarchical structure and a roughly oriented one-dimensional (1D) nanowire of WO₃ are selectively prepared on an alumina substrate by an induced hydrothermal growth method. Each hierarchical structure is constructed hydrothermally through bilateral inductive growth of WO₃ nanowire arrays from a nanosheet preformed on the substrate. Only roughly oriented 1D WO₃ nanowire can be obtained from a spherical induction layer. The analyses show that as-prepared 1D nanowire and 3D hierarchical structures exhibit monoclinic and hexagonal phases of WO₃, respectively. The gas-sensing properties of the nanowires and the hierarchical structure of WO₃, which include the variations of their resistances and response times when exposed to NO₂, are investigated at temperatures ranging from room temperature (20 °C) to 250 °C over 0.015 ppm–5 ppm NO₂. The hierarchical WO₃ behaves as a p-type semiconductor at room temperature, and shows p-to-n response characteristic reversal with the increase of temperature. Meanwhile, unlike the 1D nanowire, the hierarchical WO₃ exhibits an excellent response characteristic and very good reversibility and selectivity to NO₂ gas at room temperature due to its unique microstructure. Especially, it is found that the hierarchical WO₃-based sensor is capable of detecting NO₂ at a ppb level with ultrashort response time shorter than 5 s, indicating the potential of this material in developing a highly sensitive gas sensor with a low power consumption. (paper)

[en] VO_x·nH₂O (2.0≤x≤2.5) nanoribbons have been synthesized by direct hydrothermal processing of the aqueous solution of NH₄VO₃ and polyethylene glycol 400 (PEG-400) at pH 3.5-5.5. Techniques of XRD, SEM, TEM, HRTEM, ED, and XPS have been used to characterize the structure, morphology, and composition of the nanoribbons. The VO_x·nH₂O nanoribbons are up to ∼200 μm in length, 100-150 nm in width, 20-30 nm in thickness, and grow along the [010] direction. The ratios of V⁴⁺ to V⁵⁺ in the products can be readily controlled by carefully adjusting the periods of reaction time. PEG carries the roles of both transport and reducing agent. A coordination self-assembly mechanism was proposed to elucidate the formation of the VO_x·nH₂O nanoribbons

[en] Recently, the Advanced Laser Interferometer Gravitational-wave Observatory detected gravitational-wave (GW) transients from mergers of binary black holes (BHs). The system may also produce a wide-angle, relativistic outflow if the claimed short gamma-ray burst detected by GBM is in real association with GW150914. It was suggested that mergers of double neutron stars (or neutron star-black hole binaries), another promising source of GW transients, also produce fast, wide-angle outflows. In this paper, we calculate the high-energy gamma-ray emission arising from the blast waves driven by these wide-angle outflows. We find that TeV emission arising from the inverse-Compton process in the relativistic outflow, originating from mergers of binary BHs that are similar to those in GW150914, could be detectable by ground-based Imaging Atmospheric Cherenkov Telescopes such as the Cherenkov Telescope Array (CTA) if the sources occur in a dense medium with a density of $n\gtrsim <!--\; ???\; -->0.3{\mathrm{c}\mathrm{m}}^{-<!--\; ???\; -->3}$. For neutron star–neutron star (NS–NS) and NS–BH mergers, TeV emission from the wide-angle, mildly relativistic outflow could be detected as well, if it occurs in a dense medium with $n\gtrsim <!--\; ???\; -->10\text{--}100{\mathrm{c}\mathrm{m}}^{-<!--\; ???\; -->3}$. Thus, TeV afterglow emission could be a useful probe of the environment of the GW transients, which could shed light on the evolution channels of the progenitors of GW transients.

[en] Ultrathin VO_2 nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO_2 nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO_2 morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO_2 nanobelts at 350 °C in air results in the formation of V_2O_5 nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V_2O_5 nanobelt networks-based sensor are investigated in a temperature range from 100 °C to 300 °C over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V_2O_5 nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 °C. (paper)

[en] Trichel pulses of negative corona discharge in atmospheric air are investigated in a needle-to-plate configuration. Time-resolved images of the pulsed discharge are recorded by using an ICCD camera. Light emission spectra of N₂ molecules and ${\text{N}}_2^{+}$ ions during the discharge are measured by optical diagnostics. The distributions of the positive ${\text{N}}_2^{+}$ ions and the reduced electric field along the discharge channel are analyzed accordingly. The results show that the positive ions that can accumulate in space and distort the electric field play an important role on the formation of the Trichel pulse. The Trichel pulse is a mode transition between low-current Townsend discharge and high-current glow discharge. The rising time of the pulse corresponds to the breakdown and formation of glow discharge, and the decay time is related to destroy the process of positive ion clouds and the quenching of glow discharge. The time interval between the pulses is determined by the re-accumulation of positive ions near the cathode in the low-current Townsend discharge to form the positive ion clouds as well as a strongly-distorted electric field. (paper)

[en] With the gradual development of Zhejiang electricity spot market, as one of the important generators in Zhejiang electricity market, nuclear power units need to adjust their strategies to participate in the spot market in order to cope with the risk of the spot market and ensure reasonable benefits. This paper first analyzes the operation characteristics of nuclear power units and the clearing process of Zhejiang electricity spot market, then formulates two different spot market bidding strategies for nuclear power units, and discusses the characteristics and applicable conditions of the two bidding strategies. Finally, IEEE 30-bus system is taken as an example to simulate the clearing process and results of the spot market under different load respectively, and some suggestions on the bidding of nuclear power units in the spot market are put forward. (authors)